Thursday, July 05, 2007

Why Teach Evolution

Apropos of some arguments about home schooling, vouchers, Christian fundamentalists, and related issues that I've been having online, it occurs to me that there are four different reasons to teach the theory of evolution as part of K-12 education:

1. It undermines religious belief. More precisely, it provides a convincing rebuttal to the watchmaker argument for the existence of God, which is one of the more persuasive arguments for that conclusion.

2. It is intellectually interesting.

3. It is useful for teaching other things, mainly biology.

4. Understanding it is useful to most students for making sense of the world around them and making decisions relevant to their lives.

The first seems to me a good reason for parents to teach their children about evolution but a suspect reason to teach it in the public schools; under a system of separation of church and state, the government shouldn't be going out of its way to attack religion any more than it should be going out of its way to promote it.

The second is a good reason but not a very strong one, given that there are lots of intellectually interesting things that could be taught, many of which, given limited amounts of time, won't be.

The third is a good reason but again not a very strong one; high school students don't learn much biology and most of what they learn could probably be taught without explaining the underlying logic of why organisms are as they are.

The fourth, I think, is the best reason of all--but the fourth depends on actually teaching the implications of evolution, which is unlikely to happen in public (or most private) schools. To take the most obvious one, evolution implies that we are "as if designed" for reproductive success. Males and females play strikingly different roles in reproduction. Hence evolutionary theory strongly suggests that males and females should have lots of differences--not merely reproductive machinery but distribution of abilities, behavioral patterns, and the like. That prediction is strongly supported by empirical evidence. For a good popular account, see Wright The Moral Animal. But it is an implication inconsistent with a good deal of modern ideology, most obviously the main--but not only--strain of modern feminism.

There are quite a lot of other implications for our species. For instance, theory suggests and evidence supports a pattern for species such as ours, with pair mating and offspring that require substantial care, of monogamy tempered by adultery, with good evolutionary reasons for both the monogamy and the adultery.

While there are surely some people who find none of the implications offensive--myself, for instance--I doubt they make up even a large minority of the population. Hence we are unlikely to see the parts of evolutionary theory most useful to ordinary people--its implications for understanding our own species--taught.

I see evolution as a carefully designed process. However, I intend to teach children what they are interested in, and not what I think is useful for them. Showing a palette and let them chose: they'll chose the right things to learn. If you are religious, think of it as God shows them the right way and the right choices - this is consistent with the writings. If you think in terms of evolution, think about children as a heavily choosen branch of the human race: the people who have made it to be here. They will make the right choices about what to learn - evolution always makes the right decisions.

I think you give too little weight to numbers two, three, and four. Yes, there are lots of interesting things that can't be taught; but in my judgment, evolutionary theory, when properly understood, is very near the top of the list of the most interesting ideas man has stumbled upon. (Relativity and QM are also up there, but they are not nearly as easy to understand as evolutionary theory is, so the expected payoff is greater from teaching evolution.)

Numbers three and four are related. As Dobzhansky said, "Nothing in biology makes sense except in the light of evolution." And biology isn't just one of the major sciences we seek to teach in school; knowledge of it can be very empowering in one's personal life as well. Nutrition and disease, for example, are important issues in nearly everyone's life, and are each best understood, IMO, in terms of evolutionary biology.

I've joked for some time that the optimal number of wives for a human male, based on sexual dimorphism in body mass, is around 1.25. So a man who has one will be unsatisfied, and one who has two will be overstressed. Which actually seems to fit the human behavior I've seen. . . .

I don't think reason 3 is as weak as you suppose. Evolution isn't just a biological idea or theory; it's the central explanatory category of biology, one without which none of the rest of it makes sense. If you're going to teach science just as a bunch of empirical observations to be memorized, you may be able to do without it, like teaching physics without mentioning conservation laws; but that really takes the life out of science. After all, there are huge numbers of facts about other things that we could ask kids to memorize just as well. But if you want to convey the excitement of science, most of it resides in the grand unifying theories.

Consider, for example, how Ayn Rand's foundational arguments in ethics go astray by assuming that every organ and function of a living body exists to further the survival of the individual organism—a hangover from Aristotelianism, I think. Narrowly, she doesn't take into account the functions of the gonads, the external genitalia, or the mammaries; broadly, she doesn't consider that individual survival itself is a means to longer-term ends, or, in less teleological language, is selected for its capacity to contribute to inclusive fitness.

There's also the fact that the theory of evolution is the pattern for many other theories of emergent spontaneous order, starting with the economics of the market—though of course the influence originally went the other way, with Darwin borrowing from economic theory. Being able to see economic markets, linguistic change, biological evolution, and the growth of scientific theories as sharing certain features makes them all more understandable. Perhaps if ecologists thought more about the actual basis of the science of ecology they would be more sympathetic to markets as institutions, for example.

As the son of a biology professor, I second what William said. It would make more sense to teach physics without inertia than to teach biology without evolution. Evolution is the central unifying principle; without it, you've just got a bunch of random unrelated facts.

Second, I think it's very critical that people understand some field of science. Without understanding the scientific method, you'll have a huge gap in your understanding of how to evaluate opposing claims in many areas of public debate. I very much doubt that anyone comes to an understanding of the scientific method in the abstract; you've got to get into some particular area of science and follow how hypotheses were formed and tested.

That could be any scientific field, but if you've got to pick one for people in general, biology is probably the best choice. It can be taught in considerable detail without getting into mathematics or statistics; I think that if you take the math and stats out of any other scientific field, you take away at least the means of testing the theories, if not the correct formulation of the theories themselves. (Actual biological research nowadays is likely to be statistical, but they're still working from a basis that was reached from just a qualitative understanding.)

Third, since very few school teachers are mathematically talented, biology is probably the only science that there's any hope of getting taught well before college for more than a small minority of the students.

Fourth, evolutionary biology is highly relevant to many other fields. It's a model for order arising from chaos through selective pressures that also helps understand free markets, the internet, etc. It helps you understand what's going on inside your own body, and understand what your doctor is telling you.

A thorough understanding of the principles of evolution can also allow someone to use that understanding to change or critique the environment around them.

An example that comes to mind from my own experience is the work environment. As a corporate manager, the company work environment can be changed through understanding what outcome you are looking for and then applying select pressures to that environment. Natural selection will then cause the population to change based on those new environmental pressures. In this case, the selection is based on who quits their jobs and who is hired instead of reproduction, but the principle holds.

Another area that evolution may provide understanding into is in politics. Political parties apply specific strategies to change the political environment which cause some people to vote and others to refrain (due to disinterest, disgust, etc. with the political process). Essentially, an artificial environmental pressure has resulted in natural selection by some people removing themselves from the environment (non-voters).

Considering the many ways that our environment is artificially, and intentionally, pressured, it may be more important than ever for students to understand these principles.

Teach evolution to kindergartners? Sounds more like indoctrination than education. Most are just learning how to drink milk through a straw at that age.

Evolution may be intellectually interesting, but so is Sudoku, and I'd bet most pre-schoolers would find that more fun.

Three is a fair point, but one can learn and understand a tremendous amount of biology without ever considering evolution. You really can.

Reason four I can't grok at all.

Specifically:

Males and females play strikingly different roles in reproduction.

They sure do, and it's been pretty well worked out what those roles are, unaided as that was by the theory of evolution.

and then this:

- but the fourth depends on actually teaching the implications of evolution, which is unlikely to happen in public (or most private) schools.

Unlikely, because frankly it's ludicrous.

I can just imagine how teaching the implications of evolution, as you imagine them, would play in middle America:

"Jimmy, you were 'as if designed' by natural selection for reproductive success. The Neo-Darwinian hypothesis - remember, we discussed that last class period? - predicts your genes want to copy themselves, you're merely the vehicle. Right. So anyway, Sally over there is entering her first estrus. She's plenty cute, what's your holdup, get in there!"

But this one takes the cake:

[evolution is] useful to most students for making sense of the world around them and making decisions relevant to their lives.

That's got to be one of the most bizarre claims re:evolution that I've ever heard. Ask any large number of students - hell, any large number of people, period - what idea or ideas have been most influential in shaping their lives and their understanding of the world around them, and I am prepared to give you a great deal of money for every one that includes in their answer, "The theory of evolution."

Actually, the weakest part of the theory of evo lies in the evidence of the way human beings behave, which in a great many cases is unarguably contrary to how neo-Darwinism predicts they should behave, if the theory were true. David Stove elaborated these ideas in his book, Darwinian Fairytales. Don't be misled by the title; the book is interesting if for no other reason than Stove was an atheist, a harsh critic of I.D., he had a pretty good handle on the theory (both old & neo), and not all of his arguments are correct.

Evolution is one of many instances of the spontaneous emergence of order, which we have only recently begun to grasp. This has huge implications for those who see imposing rules on others as the only way order can be established. As such, it is a crucial part of the intellectual equipment of any educated person. However, there is a gap between 'everyone ought to know this' to 'schools must teach this'. The educational mess we are in arises from the latter sentiment, maybe we need to ditch it, and confine our concerns to our own children's education, not everyone else's

"Jimmy, you were 'as if designed' by natural selection for reproductive success. The Neo-Darwinian hypothesis - remember, we discussed that last class period? - predicts your genes want to copy themselves, you're merely the vehicle. Right. So anyway, Sally over there is entering her first estrus. She's plenty cute, what's your holdup, get in there!"

Ah, but you're only talking about Jimmy's reproductive success. Sally's reproductive success is not likely to be enhanced by mating unselectively with the first random male who comes along, especially one who lacks the economic resources to share the cost of raising a child, the legal right to commit himself to doing so through marriage, and quite likely the motivation to do so. Especially since Sally is likely too young to be either fully fertile or optimally able to carry a pregnancy to term; and her own economic ability to support a pregnancy and raise a child will be much higher after ten more years of education.

Conceivably the study of evolution might encourage young women to estimate the costs and benefits of sexual behavior more prudently.

In any case, it's silly to argue against teaching evolution based on a pop-Darwinian straw man reading of its implications. It's like arguing against it based on claims about the evils of "social Darwinism"—when social Darwinism did not necessarily follow validly from the actual theory of evolution anyway, but more from literary slogans inspired by it. (Actually, I've read some of the works of the two leading social Darwinists, Herbert Spencer and William Graham Sumner, and neither one's ideas were much like the popular image of "social Darwinism" as an ideology anyway, but that's another story.)

There is not much connection between how we used a feature when it was evolving and what we do or don't do with that feature today. We are for instance splendid running machines, and probably evolved in circumstances that required running several dozen miles in a single day. You miss it? I thought not. If someone were to suggest that your willingness to run 25 miles at a crack was a valid test of how well you understood evolution you would, I bet, think the argument a weak one.

I think reason #2 is a tremendous understatement. The theory of natural selection is one of the most radical and influential ideas in the history of human thought. Like Copernicus' theory that the earth revolves around the sun, it is both powerful and shocking. But by your argument, why even teach Copernicus in school? It's not like high schoolers "need to know" about the solar system to go about their daily lives.

Actually, Darwin ties in very closely with Adam Smith's "invisible hand" -- the idea that spontaneous organization can appear as if it were intentionally designed. This idea has ramifications far beyond just biology and economics.

I've been explaining as much biology through evolution as possible to my 6 year old. You're not going to get to inclusive fitness or neutral evolution at this age, but you can definitely get the idea that the stuff that survived and had kids *didn't* get eaten by something else, didn't starve because all its prey animals could outrun it, etc. Really understanding stuff like Monarch/Viceroy butterflies, brightly colored poisonous frogs, animals that are good at hiding, etc., is a lot easier when you think from that perspective.

This won't be the level of understanding he always has of things, but you've got to answer the questions of a curious kid somehow, and the truth as best you understand it seems like the best kind of answer. It's fun watching him see some animal in the zoo, think for a minute, and ask "what's its defense?"

First, evolution is not a rebuttal against the watchmaker analogy. The watchmaker argument refers to the universe, not biology by itself.

Evolution does rebut the watchmaker argument when the watchmaker is invoked to explain life on earth. This is probably its most common use. The watchmaker argument can also be deployed to "explain" the origin and development of the universe, and a different set of arguments - cosmology - is used to rebut that.

I think the best reason to teach evolution is a combination of 2&4. Biological evolution is how science answers the question "How did I get to be this conscious thinking being with this particular physical form and these particular desires?" I think it's enormously important to know about this theory when building a view of the world.

That religions object, as science, with the theory of evolution makes an intrusion in to the market of beliefs monopolized by religions should be expected. It is just rent seeking (which is, i would argue, bad for the average guy). Also, there can be remarkable switching costs when changing from a system of belief to another. That is why religious people who fancy themselves rational don't want to hear about evolution.

Maybe schools should teach all 'theories' of creation/evolution with no specific emphasis on any one of those theories. This way the ppl could pick the one they want to believe into. The fact is, however, that only one of these is scientific and based on criticial thinking and evidence, and (to my mind) so much better than the others.

I'm curious why you do not suggest introducing creationism as well. This is an opportunity to teach the idea of models and how models are based on evidence. It seems unfortunate that kids are not taught that most of what we profess in science are only theories (with some theories better than others).

Reason 1. I don't that because something undermines somebodies believe, can be an argument neither to teach nor not to teach something in school. This would mean that what is taught in school would be influenced on the believe (in a religious sense) which would collide with the separation of church and state. I can't really judge if reason 2. to 4. are sufficient to teach the theory of evolution. But clearly none of these reasons apply to teaching intelligent design.

(1) Refuting the watchmaker argument does not really undermine religious belief because (a) the watchmaker argument is not part of any religion's dogma (it is only a proposed support for dogmas) and (b) the watchmaker argument does not support monotheism.

(2) Evolution is one of the first few really creative modelling inventions since the ancient Greeks. It ranks right up there with the calculus. That's more than merely "interesting".

(3) As others point out, it is the unifying explanatory principle throughout the life sciences and the infosphere (or memosphere?)

(4) This is the only point I agree with, except that I don't think it contradicts much feminism. Perhaps it contradicts the "Men ought to have the right to have babies too" strawmen from "The Life Of Brian", but mainstream feminism isn't afflicted with biological nonsense that I've heard.